These nice gold coins bear inscriptions NAPOLEON EMPEREUR and EMPIRE FRANCAIS or REPUBLIQUE FRANCAISE with a wreath on the back and sometimes with laurel leaves around Napoleon's head. All these coins are valuable because they contain gold, as follows:

20 FRANCS: 0.1867 troy ounces gold40 FRANCS: 0.3734 troy ounces

You can compute the base value (BV) of the coin by multiplying the weight of gold by the current price of gold. The price changes every day, so you must do the calculation afresh. On the day of this appraisal, gold was selling at $1470 US dollars per troy ounce, so the BV for a 20 france coin was 0.1867 x 1470 = 275.

But these coins are more valuable than the base value, especially when they are in good condition. Here are some typical additions to BV for these coins (be sure to read modifiers below):